package duan.entity;
/*** goods 商品实体类* @author duan*/
public final class Goods
{//数据库Goods表主鍵private static int count=0;private int gid;private String gname;private double gprice;private int gnum;/*** 添加商品信息* @param gname,gprice,gum*/public Goods(String gname,double gprice,int gum){this.gname  = gname;this.gprice = gprice;this.gnum 	= gum;count++;gid = count;}/*** 展示所有商品* @param gid,gname,gprice,gum*/public Goods(int gid,String gname,double gprice,int gum){this.gid	= gid;this.gname  = gname;this.gprice = gprice;this.gnum 	= gum;}/*** 根据编号更改商品信息* @param gid,gum*/public Goods(int gid,int gnum){this.gid	= gid;this.gnum 	= gnum;}/*** 根据编号更改商品信息* @param gid,gprice*/public  Goods(int gid,double gprice){this.gid	= gid;this.gprice = gprice;}/*** 根据编号更改商品信息* @param gid,gname*/public  Goods(int gid,String gname){this.gid	= gid;this.gname  = gname;}//共有-get、set-方法。public int getGid(){return gid;}public void setGid(int gid){this.gid = gid;}public String getGname(){return gname;}public void setGname(String gname){this.gname = gname;}public double getGprice(){return gprice;}public void setGprice(double gprice){this.gprice = gprice;}public int getGnum(){return gnum;}public void setGnum(int gnum){this.gnum = gnum;}						
}

package duan.entity;/*** Gsales g购物结算实体类* @author duan*/public final class Gsales
{	private static int count;private int gsid;private int gId;private int sId;private int sNum;private String gName; private double gPrice;private int gNum;/*** 购物结算* @param gId,sId,sNum*/public Gsales(int gId,int sId, int sNum){this.gId = gId;this.sId = sId;this.sNum = sNum;count++;setGsid(count);}/*** 展现商品列表* @param gName,gPrice,gNum,allSnum*/public Gsales(String gName,double gPrice,int gNum){this.gName = gName;this.gPrice = gPrice;this.gNum = gNum;}//共有set、getpublic int getGId(){return gId;}public void setGId(int id){gId = id;}public int getSId(){return sId;}public void setSId(int id){sId = id;}public int getSNum(){return sNum;}public void setSNum(int num){sNum = num;}public String getGName(){return gName;}public void setGName(String name){gName = name;}public double getGPrice(){return gPrice;}public void setGPrice(double price){gPrice = price;}public int getGNum(){return gNum;}public void setGNum(int num){gNum = num;}public int getGsid() {return gsid;}public void setGsid(int gsid) {this.gsid = gsid;}}

package duan.entity;/*** SalesMan 售货员实体类* @author duan*/public final class SalesMan
{	private static int count;private int sId;private String sName;private String sPassWord;/*** 验证用户登陆* @param sId,spassWord*/public SalesMan(int sId,String spassWord){this.sId = sId;this.sPassWord = spassWord;}/*** 查询用户、更改用户密码* @param sId,sName,sPassWord*/public SalesMan(int sId,String sName,String sPassWord){this.sId = sId;this.sName = sName;this.sPassWord = sPassWord;}/*** 添加用户* @param NsNameame,sPassWord*/public SalesMan(String NsNameame, String sPassWord){this.sName = NsNameame;this.sPassWord = sPassWord;count++;sId = count;}//共有get.set方法public int getSId(){return sId;}public void setSId(int id){sId = id;}public String getSName(){return sName;}public void setSName(String name){sName = name;}public String getSPassWord(){return sPassWord;}public void setSPassWord(String passWord){sPassWord = passWord;}}

1.所有实体中，域中的字段都是private的，然后又get和set方法获取和设置字段，体现了封装的思想。

2.每个实体都有一个static的count字段。构造方法里面都有count++，用来自动生成ID号，然后再将这个值赋予各自的ID，这样就能每新建一个实体都自动生成一个ID，缺点就是，如果程序不是第一次启动，数据库里面可能已经有值了，而这个count还默认从0开始，这时候加入数据库就会出错，因为所有ID值在数据库里面都是对应的主键。完善的方法是count的初始值从数据库里面读取。

3.每个实体的构造方法都有不同的重载方法，这样调用时就会更加灵活和方便。

4.为了源码完整性，补充tool包，后面就不分析啦。

package duan.tools;import java.util.Scanner;import duan.page.GoodsPage;
import duan.page.MainPage;
import duan.page.SalesManPage;/*** 1.各種完成操作后的 选择下一步* 2.界面选择操作* @author duan*/public class ScannerChoice
{/*** @return double 键盘获取商品价格,小数点后两位*/public static double ScannerInfo(){double num = 0.00;do{Scanner sc = new Scanner(System.in);System.out.print("保留小数点后两位,请输入：");String info = sc.next();String regex = "(([1-9][0-9]*)\\.([0-9]{2}))|[0]\\.([0-9]{2})";//保留小数点后2位小数if (info.matches(regex)){num = Double.parseDouble(info);}else {System.err.println("！输入有误！");continue;}break;} while (true);return num;}/*** @return int 键盘获取商品数量*/public static int ScannerNum(){int num = 0;String regex = "([1-9])|([1-9][0-9]+)";//商品数量do{Scanner sc = new Scanner(System.in);System.out.print("请输入：");String nums = sc.next();if (nums.matches(regex)){num = Integer.parseInt(nums);}else {System.err.println("！输入有误！");continue;}break;} while (true);return num;}/*** @return String 获取的键盘输入*/public static String ScannerInfoString(){Scanner scanner = new Scanner(System.in);System.out.print("请输入：");return scanner.next();}/*** 获取用户-更改完商品-下一步* 获取用户-删除完商品-下一步* 获取用户-添加完商品-下一步* @param 调用者*/public static void changedInfoNext(String oper){		do{System.out.println("是否继续进行-当前操作:(Y/N)");String choice = ScannerChoice.ScannerInfoString();//在JAVA中: Equals比较的是值,==比较的是地址if ("y".equals(choice) || "Y".equals(choice)) {//下面的嵌套if-else 是让用户选择继续操作当前步骤所跳转到指定页面。（因为不同函数调用，跳转的指定函数不同）if ("upateGoodsPage".equals(oper)){GoodsPage.updateGoodsPage();}else if ("deleteGoodsPage".equals(oper)) {GoodsPage.deleteGoodsPage();}else if ("addGoodsPage".equals(oper)){GoodsPage.addGoodsPage();}//上面的嵌套结束}else if ("N".equals(choice) || "n".equals(choice)) {MainPage.MaintenancePage();}System.out.println("\n输入有误！请重新输入.");} while (true);}/*** 获取用户-更改-完售货员-下一步* 获取用户-添加-完售货员-下一步* 获取用户-查询-完售货员-下一步* 获取用户-删除-完售货员-下一步* @param 调用者*/public static void choiceSalesManNext(String oper){	do{		System.out.println("是否继续进行-当前操作:(Y/N)");String choice = ScannerChoice.ScannerInfoString();if ( "y".equals(choice) || "Y".equals(choice) ) {//下面的嵌套if-else 是让用户选择继续操作当前步骤所跳转到指定页面。（因为不同函数调用，跳转的指定函数不同）if ("updateSalesMan".equals(oper)){SalesManPage.updateSalesManPage();}else if ("deleteSalesMan".equals(oper)) {SalesManPage.deleteSalesManPage();}else if ("addSalesMan".equals(oper)){SalesManPage.addSalesManPage();}else if ("querySalesMan".equals(oper)) {SalesManPage.querySalesManPage();	} //上面的嵌套结束}else if ("N".equals(choice) || "n".equals(choice)) {MainPage.salesManManagementPage();}System.err.println("\t输入有误！");} while (true);}	}

package duan.tools;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;import duan.dao.GoodsDao;
import duan.db.DbClose;
import duan.db.DbConn;
import duan.entity.Goods;
import duan.entity.SalesMan;/*** 查询&&打印 函数工具(后期优化可能会删)*@author duan*/public final class QueryPrint
{Connection        conn  = null;PreparedStatement pstmt = null;ResultSet 		rs 	 	 = null;/*** 模糊查询并陈列查询信息函数小工具* @param oper 调用者* @return 查询到的信息的gid,如果返回值等于-1，则代表查询异常。	  */public static int query(String oper){int gid = -1;String shopping = ScannerChoice.ScannerInfoString(); //键盘获取商品名字ArrayList<Goods> goodsList = new QueryPrint().queryGoodsKey(-1,shopping);  //根据键盘获取的商品名字調用 精确查询函数，確定用戶所要操作的数据if (goodsList == null || goodsList.size() <= 0){System.err.println("\t！！查无此商品 ！！");//調用选择下一步函数ScannerChoice.changedInfoNext(oper);}else	//查到有此商品，实现进行 更改商品 信息操作！{		Goods goods = goodsList.get(0);System.out.println("\t\t\t\t\t商品列表\n\n");System.out.println("\t商品编号\t\t商品名称\t\t商品价格\t\t商品数量\t\t备注\n");System.out.print("\t"+goods.getGid()+"\t\t"+goods.getGname()+"\t\t"+goods.getGprice()+"\t\t"+goods.getGnum());if (goods.getGnum()==0){System.out.println("\t\t该商品已售空");}else if (goods.getGnum()<10){System.out.println("\t\t该商品已不足10件");}else {System.out.println("\t\t-");}gid = goods.getGid(); //将商品编号返回给调用者}return gid;} /*** 模糊查询函数小工具* @return int 当商品件数有且只有一件时返回商品gid号，商品已售空时返回 -1. >1件时返回-2 . 查无此商品时返回-3* 					  */public static int querySettlement() {int gid = -1;ArrayList<Goods> goodsSettlement = new GoodsDao().queryGoods(3);//調用 关键字查询函数if (goodsSettlement == null || goodsSettlement.size() <= 0){System.err.println("\t！！查无此商品 ！！\n");gid = -3;	}else	//查到有此商品，实现进行 更改商品 信息操作！{	System.out.println("\t\t\t\t\t商品列表\n\n");System.out.println("\t商品编号\t\t商品名称\t\t商品价格\t\t商品数量\t\t备注\n");for (int i = 0; i < goodsSettlement.size(); i++){Goods goods = goodsSettlement.get(i);if (goods.getGnum() > 0){System.out.print("\t"+goods.getGid()+"\t\t"+goods.getGname()+"\t\t"+goods.getGprice()+"\t\t"+goods.getGnum());if (goods.getGnum()==0){System.out.println("\t\t该商品已售空");}else if (goods.getGnum()<10){System.out.println("\t\t该商品已不足10件");}else {System.out.println("\t\t-");}if (goodsSettlement.size()==1){gid = goods.getGid(); //将商品编号返回给调用者}else {gid = -2;}}}}return gid; } /*** 根据商品 gid or gName查询商品* @param 商品id,商品名称* @return 商品信息*/public ArrayList<Goods> queryGoodsKey(int gId,String gName) {										ArrayList<Goods> goodsList = new ArrayList<Goods>();conn = DbConn.getconn();	String sql = "SELECT * FROM GOODS WHERE GID=? OR GNAME=?"; try{pstmt = conn.prepareStatement(sql);pstmt.setInt(1, gId);pstmt.setString(2, gName);rs = pstmt.executeQuery();while (rs.next()){int gid = rs.getInt("gid");String gname = rs.getString(2);double gprice = rs.getDouble(3);int gnum = rs.getInt(4);Goods goods = new Goods(gid,gname,gprice,gnum);goodsList.add(goods);}} catch (SQLException e){e.printStackTrace();}finally{DbClose.queryClose(pstmt, rs, conn);}return goodsList;}	/*** 精确查询售货员信息* @param 售货员名字* @return */public ArrayList<SalesMan> querySalesMan(String sName){ArrayList<SalesMan> SalesManList = new ArrayList<SalesMan>();conn = DbConn.getconn();	String sql = "SELECT * FROM SALESMAN WHERE SNAME=?";try{pstmt = conn.prepareStatement(sql);pstmt.setString(1, sName);rs = pstmt.executeQuery();while (rs.next()){int sid = rs.getInt("sid");String sname = rs.getString(2);String sPassWord = rs.getString(3);SalesMan salesMan = new SalesMan(sid,sname,sPassWord);SalesManList.add(salesMan);}} catch (SQLException e){e.printStackTrace();}finally{DbClose.queryClose(pstmt, rs, conn);}return SalesManList;}
}

package duan.tools;import java.math.BigDecimal;/**  * 由于Java的简单类型不能够精确的对浮点数进行运算，这个工具类提供精  * 确的浮点数运算，包括加减乘除和四舍五入.* * 注意：此代码将加减乘除四舍五入方法已实现，但本项目中并未全部使用.* @author lyons(zhanglei)*/  public class Arith
{private static final int DEF_DIV_SCALE = 2; //默认除法运算精度private Arith(){} /**  * 提供精确的加法运算。  * @param v1 被加数  * @param v2 加数  * @return 两个参数的和  */  public static double add(double v1,double v2){   BigDecimal b1 = new BigDecimal(Double.toString(v1));   BigDecimal b2 = new BigDecimal(Double.toString(v2));   return b1.add(b2).doubleValue();   } /**  * 提供精确的减法运算。  * @param v1 被减数  * @param v2 减数  * @return 两个参数的差  */  public static double sub(double v1,double v2){   BigDecimal b1 = new BigDecimal(Double.toString(v1));   BigDecimal b2 = new BigDecimal(Double.toString(v2));   return b1.subtract(b2).doubleValue();   }   /**  * 提供精确的乘法运算。  * @param v1 被乘数  * @param v2 乘数  * @return 两个参数的积  */  public static double mul(double v1,double v2){   BigDecimal b1 = new BigDecimal(Double.toString(v1));   BigDecimal b2 = new BigDecimal(Double.toString(v2));   return b1.multiply(b2).doubleValue();   }   /**  * 提供（相对）精确的除法运算，当发生除不尽的情况时，精确到  * 小数点以后2位，以后的数字四舍五入。  * @param v1 被除数  * @param v2 除数  * @return 两个参数的商  */  public static double div(double v1,double v2){   return div(v1,v2,DEF_DIV_SCALE);   }   /**  * 提供（相对）精确的除法运算。当发生除不尽的情况时，由scale参数指  * 定精度，以后的数字四舍五入。  * @param v1 被除数  * @param v2 除数  * @param scale 表示表示需要精确到小数点以后几位。  * @return 两个参数的商  */  public static double div(double v1,double v2,int scale){   if(scale<0){   throw new IllegalArgumentException(   "The scale must be a positive integer or zero");   }   BigDecimal b1 = new BigDecimal(Double.toString(v1));   BigDecimal b2 = new BigDecimal(Double.toString(v2));   return b1.divide(b2,scale,BigDecimal.ROUND_HALF_UP).doubleValue(); //BigDecimal.ROUND_HALF_UP 向“最接近的”数字舍入，如果与两个相邻数字的距离相等，则为向上舍入的舍入模式。 }   /**  * 提供精确的小数位四舍五入处理。  * @param v 需要四舍五入的数字  * @param scale 小数点后保留几位  * @return 四舍五入后的结果  */  public static double round(double v,int scale){   if(scale<0){   throw new IllegalArgumentException("The scale must be a positive integer or zero");   }   BigDecimal b = new BigDecimal(Double.toString(v));   BigDecimal one = new BigDecimal("1");   return b.divide(one,scale,BigDecimal.ROUND_HALF_UP).doubleValue();   }   
}